Things are pretty different now from when I started out.. you have all sorts of resources, like Talk Bass, that just weren't available then.
I started playing bass in 1979, I think.. possibly 1980. Back then, and where I lived, the options for learning were slim and none. I took the route of picking things off the record.
First, I was a lazy guy and didn't practice as much as I should, so I didn't become an awesome bassist by any means, so keep that in mind. But I also had a natural ear for music, so picking out the basslines was a bit easier for me than for many.
I decided I wanted to be a good bassist, so I swore to study the basslines of Chris Squire. When I heard Rush, sometime in 1981, I swore to get those down too.
But those are very hard, especially when you are starting out, and I also took the approach that learning a lot of easy songs was good too. I remember learning Back in Black, that sort of thing, then playing in a high school talent show.
Learning those basslines was a little easier with a record than it is without another tool right now, because I could simply put my finger on the record to slow it down so that I could hear the notes. Now this can be done even easier with an app that will slow down the song, but keep the pitch the same -- no more mental adjusting of pitch to figure out what notes are what.
The thing is, as lazy as I was, I realized I wasn't going to get anywhere without really hard work. So I actually did apply myself a bit until I had learned a lot about the progressive rock tunes I loved. At first I could approximate them, then I could get all the notes, but not the technique, then over time, everything got a little better.
But none of that happens without a lot of practice, and the practice has to be effective.
So in your case, if you are trying to play along with an Abba song, and you get lost -- stop the song. Break it into chunks; say the intro and first verse could be one chunk. Play the sheiza out of that until you have it. Then move to the chorus -- focus only on the chorus for a while until you have it. Now go back and play from intro to chorus (you will make some mistakes at first, but don't get mad -- your brain has to stick those pieces together and it takes a little bit). Once you can play Intro through first chorus, the rest of the song can be easier because a lot of it will repeat. There may be a bridge to learn, but do it in chunks, and you will get it.
After you've learned your first one, the next one will be easier, so don't dispair if at first it seems very hard. Learning to think in a new way IS hard!
There isn't any substitute for practice and working at it. Doing the same thing over and over again is, admittedly, boring. But the satisfaction is when you can play the whole song -- even better, when you can play it in a band.
And all that other stuff about getting a teacher -- that is good advice. I should have done that when I was younger. I will have to do it now, because there is a lot I never learned.
Good luck!
I guess I'll just keep plowing on and working at it and hope that I get somewhere with it some time.
